The following does not belong to either purines or pyrimidines

Options

A. Tryptophan
B. Cytosine
C. Uracil
D. Adenine

Answer

To solve the question of which compound does not belong to either purines or pyrimidines, we will analyze the given options: tryptophan, cytosine, uracil, and adenine.

### Step-by-Step Solution:

1. **Identify the Categories**:
- Purines include adenine and guanine.
- Pyrimidines include cytosine, uracil, and thymine.

2. **Analyze Each Option**:
- **Adenine**: This is a purine base. It is part of the nucleic acids (DNA and RNA).
- **Cytosine**: This is a pyrimidine base. It is also part of nucleic acids.
- **Uracil**: This is another pyrimidine base, found only in RNA.
- **Tryptophan**: This is an amino acid, not a nitrogenous base. It does not belong to either purines or pyrimidines.

3. **Conclusion**:
- The only option that does not belong to either purines or pyrimidines is **tryptophan**.

### Final Answer:
**Tryptophan does not belong to either purines or pyrimidines.**

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